js倒计时，秒倒计时，天倒计时

按天倒计时

HTML代码1:

<Script Language="JavaScript">
<!-- Begin
  var timedate= new Date("January 14,2006");
  var times="研究生考试";
  var now = new Date();
  var date = timedate.getTime() - now.getTime();
  var time = Math.floor(date / (1000 * 60 * 60 * 24));
  if (time >= 0) ;
  document.write("<li><font color=#DEDBDE>现在离2006年"+times+"还有: <font color=#ffffff><b>"+time +"</b></font> 天</font></li>");
// End -->
</Script>

HTML代码2:

<script language="JavaScript" type="text/javascript">
function djs(){
  var urodz= new Date("11/12/2008");
  var now = new Date();
  var num
  var ile = urodz.getTime() - now.getTime();
  var dni = Math.floor(ile / (1000 * 60 * 60 * 24));
  if (dni >1)num=dni+1
  else if (dni == 1)num=2
  else if (dni == 0)num=1
  else num=0
  document.write(num)
}
</script>

距某某开幕式还有 [<script language="JavaScript" type="text/javascript">djs()</script>] 天

精确到秒的javascript倒计时代码

HTML代码:

<form name="form1">
<div align="center" align="center">
<center>离2013年还有:<br>
<input type="textarea" name="left" size="35" style="text-align: center">
</center>
</div>
</form>
<script LANGUAGE="javascript">
  startclock()
  var timerID = null;
  var timerRunning = false;
  function showtime() {
    Today = new Date();
    var NowHour = Today.getHours();
    var NowMinute = Today.getMinutes();
    var NowMonth = Today.getMonth();
    var NowDate = Today.getDate();
    var NowYear = Today.getYear();
    var NowSecond = Today.getSeconds();
    if (NowYear <2000)
    NowYear=1900+NowYear;
    Today = null;
    Hourleft = 23 - NowHour
    Minuteleft = 59 - NowMinute
    Secondleft = 59 - NowSecond
    Yearleft = 2009 - NowYear
    Monthleft = 12 - NowMonth - 1
    Dateleft = 31 - NowDate
    if (Secondleft<0)
    {
      Secondleft=60+Secondleft;
      Minuteleft=Minuteleft-1;
    }
    if (Minuteleft<0)
    {
      Minuteleft=60+Minuteleft;
      Hourleft=Hourleft-1;
    }
    if (Hourleft<0)
    {
      Hourleft=24+Hourleft;
      Dateleft=Dateleft-1;
    }
    if (Dateleft<0)
    {
      Dateleft=31+Dateleft;
      Monthleft=Monthleft-1;
    }
    if (Monthleft<0)
    {
      Monthleft=12+Monthleft;
      Yearleft=Yearleft-1;
    }
    Temp=Yearleft+'年, '+Monthleft+'月, '+Dateleft+'天, '+Hourleft+'小时, '+Minuteleft+'分, '+Secondleft+'秒'
    document.form1.left.value=Temp;
    timerID = setTimeout("showtime()",1000);
    timerRunning = true;
  }
  var timerID = null;
  var timerRunning = false;
  function stopclock () {
    if(timerRunning)
      clearTimeout(timerID);
    timerRunning = false;
  }
  function startclock () {
    stopclock();
    showtime();
  }
// -->
</script>  

某某运动会，按时间提示不同的阶段

HTML代码:

<!--倒计时Javascript begin-->
<script language="JavaScript">
<!--
function DigitalTime1()
{
  var deadline= new Date("08/13/2007") //开幕倒计时
  var symbol="8月13日"
  var now = new Date()
  var diff = -480 - now.getTimezoneOffset() //是北京时间和当地时间的时间差
  var leave = (deadline.getTime() - now.getTime()) + diff*60000
  var day = Math.floor(leave / (1000 * 60 * 60 * 24))
  var hour = Math.floor(leave / (1000*3600)) - (day * 24)
  var minute = Math.floor(leave / (1000*60)) - (day * 24 *60) - (hour * 60)
  var second = Math.floor(leave / (1000)) - (day * 24 *60*60) - (hour * 60 * 60) - (minute*60)  

  var deadline_2= new Date("08/13/2004") //开幕后计时
  var symbol_2="8月13日"
  var now_2 = new Date()
  var diff_2 = -480 - now.getTimezoneOffset() //是北京时间和当地时间的时间差
  var leave_2 = (now_2.getTime() - deadline_2.getTime()) + diff_2*60000
  var day_2 = Math.floor(leave_2 / (1000 * 60 * 60 * 24))
  var hour_2 = Math.floor(leave_2 / (1000*3600)) - (day_2 * 24)
  var minute_2 = Math.floor(leave_2 / (1000*60)) - (day_2 * 24 *60) - (hour_2 * 60)
  var second_2 = Math.floor(leave_2 / (1000)) - (day_2 * 24 *60*60) - (hour_2 * 60 * 60) - (minute_2*60)  

  day=day+1;
  day_2=day_2+1;  

  if (day>0) //还未开幕
  {
    //LiveClock1.innerHTML = "现在"+symbol+"天"
    LiveClock1.innerHTML = "<font
    setTimeout("DigitalTime1()",1000)
  }  

  if (day<0) //已经开幕
  {
    //LiveClock1.innerHTML = "现在离"+symbol+"还有"+day+"天"+hour+"小时"+minute+"分"+second +"秒"
    LiveClock1.innerHTML = "<font
    setTimeout("DigitalTime1()",1000)
  }  

  if (day==0) //正在开幕
  {
    //LiveClock1.innerHTML = "现在"+symbol+"天"
    LiveClock1.innerHTML = "<font
    setTimeout("DigitalTime1()",1000)
  }  

  if (day<0 & day_2>19) //某某运动会结束
  {
    //LiveClock1.innerHTML = "现在离"+symbol+"还有"+day+"天"+hour+"小时"+minute+"分"+second +"秒"
    LiveClock1.innerHTML = "<font
    setTimeout("DigitalTime1()",1000)
  }  

}
// -->
</script>
<!--倒计时Javascript end-->
<body onload=DigitalTime1()>
<div id= LiveClock1></div>  

</body>

按小时倒计时

HTML代码:

<SCRIPT LANGUAGE="JavaScript">
<!--
var maxtime = 60*60 //一个小时，按秒计算，自己调整!
function CountDown(){
  if(maxtime>=0){
    minutes = Math.floor(maxtime/60);
    seconds = Math.floor(maxtime%60);
    msg = "距离结束还有"+minutes+"分"+seconds+"秒";
    document.all["timer"].innerHTML=msg;
    if(maxtime == 5*60)
      alert('注意，还有5分钟!');
    --maxtime;
  }
  else{
    clearInterval(timer);
    alert("时间到，结束!");
  }
}
timer = setInterval("CountDown()",1000);
//-->
</SCRIPT>
<div id="timer" style="color:red"></div>

Javascript倒计时器 - 采用系统时间自校验

这次利用系统时间自校验倒计时, 无需手工调校使得倒计时更为精确, 代码及详细注释如下:

<span id="clock">00:01:11:00</span>
<input id="startB" type="button" value="start countdown!" onclick="run()">
<input id="endB" type="button" value="stop countdown!" onclick="stop()">
<br>
<input id="diff" type="text">
<input id="next" type="text">
<script language="Javascript">
/* This notice must be untouched at all times.

countdown.js    v. 1.0
The latest version is available at
http://blog.csdn.net/yjgx007

Copyright (c) 2004 Xinyi.Chen. All rights reserved.
Created 7/30/2004 by Xinyi.Chen.
Web: http://blog.csdn.net/yjgx007
E-Mail: chenxinyi1978@hotmail.com
Last modified: 7/30/2004

This program is free software;
you can redistribute it and/or modify it under the terms of the
GNU General Public License as published by the Free Software Foundation;

See the GNU General Public License
at http://www.gnu.org/copyleft/gpl.html for more details.
*/
var normalelapse = 100;
var nextelapse = normalelapse;
var counter;
var startTime;
var start = clock.innerText;
var finish = "00:00:00:00";
var timer = null;  

// 开始运行
function run() {
  startB.disabled = true;
  endB.disabled = false;
  counter = 0;
  // 初始化开始时间
  startTime = new Date().valueOf();  

  // nextelapse是定时时间, 初始时为100毫秒
  // 注意setInterval函数: 时间逝去nextelapse(毫秒)后, onTimer才开始执行
  timer = window.setInterval("onTimer()", nextelapse);
}  

// 停止运行
function stop() {
  startB.disabled = false;
  endB.disabled = true;
  window.clearTimeout(timer);
}  

window.onload = function() {
  endB.disabled = true;
};

// 倒计时函数
function onTimer()
{
  if (start == finish)
  {
    window.clearInterval(timer);
    alert("time is up!");
    return;
  }  

  var hms = new String(start).split(":");
  var ms = new Number(hms[3]);
  var s = new Number(hms[2]);
  var m = new Number(hms[1]);
  var h = new Number(hms[0]);  

  ms -= 10;
  if (ms < 0)
  {
    ms = 90;
    s -= 1;
    if (s < 0)
    {
        s = 59;
        m -= 1;
    }  

    if (m < 0)
    {
        m = 59;
        h -= 1;
    }
  }  

  var ms = ms < 10 ? ("0" + ms) : ms;
  var ss = s < 10 ? ("0" + s) : s;
  var sm = m < 10 ? ("0" + m) : m;
  var sh = h < 10 ? ("0" + h) : h;  

  start = sh + ":" + sm + ":" + ss + ":" + ms;
  clock.innerText = start;  

  // 清除上一次的定时器
  window.clearInterval(timer);  

  // 自校验系统时间得到时间差, 并由此得到下次所启动的新定时器的时间nextelapse
  counter++;
  var counterSecs = counter * 100;
  var elapseSecs = new Date().valueOf() - startTime;
  var diffSecs = counterSecs - elapseSecs;
  nextelapse = normalelapse + diffSecs;
  diff.value = counterSecs + "-" + elapseSecs + "=" + diffSecs;
  next.value = "nextelapse = " + nextelapse;
  if (nextelapse < 0) nextelapse = 0;  

  // 启动新的定时器
  timer = window.setInterval("onTimer()", nextelapse);
}
</script>